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Guide: iPhone 6S Short Circuit After Restarting

Received an iPhone 6S motherboard from one of our customers, the main problem is that the iPhone 6S is short circuit after restarting. How to diagnose and test the problem step by step, let's check in the article.


After receiving the iPhone 6S motherboard, we observe first and found the board is very good, it's never repaired before.


Connect iPhone motherboard to the DPS DC power supply, the current of the beginning tested is 20mA, it's normal.

When the current jumps to 40mA, which means the iPhone power and CPU starts to work. When the current jumps to 10.6mA, which mean the upper was opened.

When the current jumps to 70.8mA, which means the iPhone Nand flash starts to work. When the current jumps to 100mA, which means the CPU starts the I2C data bus, at this time, the iPhone display power IC start working, the Apple LOGO will appear on the iPhone display screen, and then the iPhone backlight start to work. At this time, the current is usually around 300mA.

When the Apple logo appears, the current on the DC power supply screen is constantly jumping，because the iPhone baseband and iPhone WiFi are being started. After the iPhone screen is lit, the current will jump back to 300mA from 500mA. 

However, when the current jumps up the second time, the iPhone motherboard is short circuit and turned off. Our preliminary judgment is that the amplifier has a problem.

First we need to check whether the power supply of amplifier is normal, after testing, every power supply of amplifier is good.

Seems it's complicated, but after thinking, we know that the iPhone amplifier IC and iPhone WIFI IC are the most power consumption parts.

Connect iPhone motherboard to DC power supply to boot it, after few second, the WIFI is overheating, the problem was found.

Heat iPhone WIFI IC by QUICK 861DW hot air rework station, and then use Titanium Alloy Tweezers to remove the iPhone WIFI IC. Now, measure it again, the current is normal, and no short-circuit phenomenon.

Install the new iPhone WIFI IC, remove the iPhone Nand flash, and then use JC Pro1000S to unbind the WIFI.

Finally, install the iPhone 6S, and test it, now the iPhone works properly.

Check more phone repair details on www.vipfixphone.com


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